JP2020158744A - Polyimide and polyimide film - Google Patents

Abstract

To provide a polyimide which has a heat resistance and a light transmittance, a good bending resistance, provides a small amount of residual solvent, and may be shape-formed in which a process load is reduced.SOLUTION: There is provided a polyimide having 20 mol% or less of the following substituent amount I, 10 mol% or less of the following substituent amount II, 20 mol% or less of total substituent amount as the total of the following substituent amount I and the following substituent amount II, and less than 5% by mass of solvent content having a boiling point of 150°C or higher. Substituent amount I: total substituent amount included in the polyimide of amic acid residue that is any one or more of an amide group, a carboxylic acid group, and a carboxylic acid ester group and any one or more of terminal groups of an amino group, a carboxylic acid group, a carboxylic acid ester group, and anhydrous carboxylic acid group. Substituent amount II: functional group amount introduced into the main chain of polyimide of any one or more of an amide group, an amino group, a nitro group, a hydroxyl group, an ester group, an alkoxy group, a halogen group, and an alkyl halide group.SELECTED DRAWING: None

Description

The present invention relates to a polyimide having heat resistance, light transmittance, a small amount of residual solvent, and good bending resistance, and a methylene chloride composition containing the polyimide. The present invention also relates to a polyimide film containing this polyimide.

In recent years, as various device applications, there has been a demand for a material having heat resistance, light transmission, a small amount of residual solvent, and good bending resistance.
For the above applications, for example, aromatic polyimide (for example, "Kapton" manufactured by DuPont) has high heat resistance and is known as a light and flexible resin. However, the aromatic polyimide has a brown color and cannot be used in applications that require high light transmission.

Therefore, the development of polyimide showing high light transmission is underway (Patent Document 1). However, in Patent Document 1, although there is a description regarding heat resistance, studies on residual solvent and bending resistance have not been sufficiently made.

Further, although polyimide is known as a heat-resistant polymer material, many of them are insoluble and insoluble, and due to their heat resistance, the molding temperature is high, heating for a long time is required, and the process load is large. If the molding temperature is lowered or the molding time is shortened while maintaining the heat resistance of the resin, the residual solvent increases and the mechanical properties deteriorate. To solve this problem, it is possible to lower the molding temperature by lowering the glass transition temperature (Tg), but the lowering of Tg tends to lower the heat resistance and other physical properties.

Patent Document 2 describes a polyimide using a specific tetracarboxylic dianhydride as a raw material as a polyimide satisfying heat resistance, low linear thermal expansion, excellent film toughness, high light transmittance, and excellent solution processability. Has been proposed. However, the polyimide of Patent Document 2 has a high molding temperature, and Patent Document 2 has not sufficiently studied the reduction of the process load and the residual solvent.

International Publication No. 2011/099518 Japanese Unexamined Patent Publication No. 2015-218179

An object of the present invention is to provide a polyimide having heat resistance and light transmittance, a small amount of residual solvent, and good bending resistance. An object of the present invention is also to provide a polyimide capable of molding with a reduced process load.
Another object of the present invention is to provide a methylene chloride composition and a polyimide film using this polyimide.

As a result of diligent studies to solve the above problems, the present inventors have found that polyimide having a specific functional group amount can solve the above problems, and have completed the present invention.

That is, the gist of the present invention is as follows.

[1] The substituent amount I defined below is 20 mol% or less, the substituent amount II defined below is 10 mol% or less, and the total sum of the substituent amount I and the substituent amount II. A polyimide having a substituent content of 20 mol% or less and a solvent content of a boiling point of 150 ° C. or higher of less than 5% by mass.
Substituent Amount I: Amic acid residue which is at least one of an amide group, a carboxylic acid group, and a carboxylic acid ester group contained in polyimide, and an amino group, a carboxylic acid group, a carboxylic acid ester group, and anhydrous. Total amount of substituents of terminal groups which are any one or more of carboxylic acid groups Amount of substituents II: Amid group, amino group, nitro group, hydroxyl group, ester group, alkoxy group introduced into the main chain of polyimide, Amount of functional group that is at least one of a halogen group and an alkyl halide group

[2] The polyimide according to [1], wherein the substituent amount I is 10 mol% or less, the substituent amount II is 8 mol% or less, and the total substituent amount is 15 mol% or less.

[3] A methylene chloride composition containing the polyimide according to [1] or [2] and having a solvent content of 5000 ppm or less having a boiling point of 150 ° C. or higher.

[4] A polyimide film containing the polyimide according to [1] or [2].

According to the present invention, it is possible to provide a polyimide having heat resistance and light transmissibility, having a small amount of residual solvent, capable of molding with a reduced process load, and having good bending resistance.
Using the polyimide of the present invention, it is possible to provide a methylene chloride composition capable of molding with a small amount of residual solvent and a reduced process load. Further, by using the polyimide of the present invention, a polyimide film having excellent bending resistance, light transmission and the like can be provided by a film forming process in which the process load is suppressed.

Hereinafter, embodiments of the present invention will be described in detail, but the examples and methods illustrated below are examples (representative examples) of the embodiments of the present invention, and the present invention does not deviate from the gist thereof. It is not limited to the contents of.

[Polyimide]
The polyimide of the present invention contains an imide ring in the main chain, and is composed of at least one selected from polyamic acid, polyamic acid ester, and polyimide.

The polyimide of the present invention has a substituent amount I defined below of 20 mol% or less, a substituent amount II defined below of 10 mol% or less, and the sum of the substituent amount I and the substituent amount II. The total amount of substituents is 20 mol% or less, and the content of the solvent having a boiling point of 150 ° C. or higher is less than 5% by mass.
Substituent Amount I: Amic acid residue which is at least one of an amide group, a carboxylic acid group, and a carboxylic acid ester group contained in polyimide, and an amino group, a carboxylic acid group, a carboxylic acid ester group, and anhydrous. Total amount of substituents of terminal groups which are any one or more of carboxylic acid groups Amount of substituents II: Amid group, amino group, nitro group, hydroxyl group, ester group, alkoxy group introduced into the main chain of polyimide, Amount of functional group that is at least one of a halogen group and an alkyl halide group

In the present invention, the amount of substituents is the ratio (mol%) of the amount of mols of substituents present in the total amount of moles of repeating units in polyimide.

[mechanism]
The reasons why the polyimide of the present invention can solve the problem of the present invention when the amount of substituents is not more than a predetermined value are considered as follows.
Generally, in order to increase the solubility of polyimide, it is better to have many polar groups, but since the solvent affinity is high when there are many polar groups, there is a large amount of residual solvent in the molded product such as the polyimide composition and the obtained polyimide film. Become.
In the polyimide of the present invention, the residual solvent (high boiling point solvent used as the reaction solvent in the production of polyimide, etc.) can be reduced by reducing the amount of functional groups by setting the amount of substituents to a predetermined value or less.
By using polyimide having a small residual solvent, a methylene chloride composition having a low content of a solvent having a boiling point of 150 ° C. or higher can be obtained.
In addition, the residual solvent of the film after film formation can be reduced, and the bending resistance is improved.
In addition, since the amount of residual solvent is small, the amount of outgas caused by the residual solvent in a process such as film formation using polyimide can be reduced to reduce the process load.
Further, when the substituent amount II is in a specific range, the interaction between the polymer chains in the polyimide is reduced, coloring due to electron transfer is suppressed, and light transmission can be improved.
The polyimide of the present invention is particularly excellent in bending resistance and light transmission and has a small amount of residual solvent, but the bending resistance, light transmission and amount of residual solvent can be evaluated by the following methods.

<Bending resistance>
The bending resistance of polyimide can be evaluated by a conventionally known method, for example, a MIT test, using a film obtained by forming a film of polyimide.

<Light transmission>
The light transmittance of polyimide can be evaluated by a conventionally known method such as ultraviolet-visible absorption, total light transmittance measurement, yellow index (YI), etc. using a film obtained by forming a film of polyimide. it can.

<Amount of residual solvent>
The amount of residual solvent in polyimide can be measured by a conventionally known method, for example, thermogravimetric analysis (TGDTA), gas chromatography (GC), NMR or the like.

[Substituent Amount I]
The amount I of the substituent of the polyimide of the present invention is usually 20 mol% or less, preferably 10 mol% or less, and more preferably 5 mol% or less. There is no limit to the lower limit of the substituent amount I.
When the amount of substituent I is not more than the above upper limit, the residual solvent of the polyimide tends to decrease, and the content of the solvent having a boiling point of 150 ° C. or higher tends to decrease in the obtained methylene chloride composition, which is preferable.
The substituent amount I is determined by the sum of the amounts of the amic acid residue (amide group, carboxylic acid group, carboxylic acid ester group) and the terminal group (amino group, carboxylic acid group, carboxylic acid ester group, anhydrous carboxylic acid group). Be done.

<Amic acid residue amount>
The amount of amic acid residue of polyimide can be determined by a conventionally known method, for example, an NMR method, an IR method, a titration method, or the like. For example, in the case of the NMR method, the amount of amic acid can be obtained from the ratio of the integral value of the peak (around 10.2 ppm) caused by the amide group of the amic acid in ¹ H-NMR and the integral value of the reference peak. .. Since the amount of substituents on the amic acid residue is 2 equivalents to the amount of the amic acid, the amount of the amic acid residue is twice the amount of the remaining amic acid.

<Terminal group>
The end group of polyimide can be obtained by a conventionally known method, for example, a method obtained from production conditions, an NMR method, an IR method, or the like. For example, when it is determined from the production conditions, it is possible to calculate the terminal species and the terminal amount from the ratio of the tetracarboxylic dianhydride used as the raw material of polyimide and the diamine compound.

[Substituent amount II]
The amount of substituent II (amide group, amino group, nitro group, hydroxyl group, ester group, alkoxy group, halogen group, alkyl halide group) introduced into the main chain of the polyimide of the present invention is usually 10 mol% or less. It is preferably 8 mol% or less. There is no limitation on the lower limit of the substituent amount II, and it may be 0 mol% (not included).
When the amount of substituent II is not more than the above upper limit, the amount of residual solvent is reduced, and the content of the solvent having a boiling point of 150 ° C. or higher in the obtained methylene chloride composition tends to be reduced, which is preferable. Further, when the amount of substituent II is not more than the above upper limit, the bending resistance and light transmittance of the obtained polyimide film tend to be improved.
The amount of substituent II introduced into the main chain can be obtained by a conventionally known method, for example, a method obtained from production conditions, an NMR method, an IR method, a GC method, or the like.
The amide group having a substituent amount II does not include an amide group based on an amic acid residue.

[Total amount of substituents]
The total amount of substituents, which is the sum of the amount of substituents I and the amount of substituents II, of the polyimide of the present invention is usually 20 mol% or less, preferably 15 mol% or less, and more preferably 10 mol% or less. The lower limit is not particularly limited, and smaller one is preferable, and zero is most preferable.
When the total amount of substituents is not more than the above upper limit, the residual solvent is small, the content of the solvent having a boiling point of 150 ° C. or higher in the obtained methylene chloride composition is small, and the bending resistance of the obtained polyimide film is reduced. It tends to have good characteristics and is preferable.

[Solvent content with boiling point of 150 ° C or higher]
The polyimide of the present invention usually contains less than 5% by mass of a solvent having a boiling point of 150 ° C. or higher, preferably 3% by mass or less, and more preferably 1% by mass or less. The lower limit is usually not particularly limited, but is preferably 0.01 ppm or more, more preferably 0.1 ppm or more, and further preferably 1 ppm or more.

When the content of the solvent is in the above range, the residual solvent in the polyimide is small, the content of the solvent having a boiling point of 150 ° C. or higher in the obtained methylene chloride composition is small, and the obtained polyimide film is resistant to bending. It is preferable because the properties such as sex tend to be good.
Further, when the amount of residual solvent is small, the amount of outgas in the process using the polyimide of the present invention is small, and the process load can be reduced.

In the present invention, the solvent having a boiling point of 150 ° C. or higher is a solvent having a boiling point of 150 ° C. or higher, which is usually used as a reaction solvent in the production of polyimide, and specifically, as a reaction solvent in the description of the method for producing polyimide described later. Among those exemplified, those having a boiling point of 150 ° C. or higher, preferably N-methyl-2-pyrrolidone (NMP) and N, N-dimethylacetamide (DMAc) can be mentioned.

Since the solvent having a boiling point of 150 ° C. or higher has a high boiling point, it cannot be efficiently removed even if the polyimide is dried after the production of the polyimide. As described above, the amount of functional groups of the polyimide of the present invention The content of this solvent can be reduced by the small amount.

[Imidization rate of polyimide]
The imidization rate of the polyimide of the present invention is not particularly limited, but is usually 90% or more, preferably 95% or more, more preferably 97.5% or more, and the upper limit of the imidization rate is 100%. When the imidization ratio is in this range, dehydration due to imide ring closure during molding is reduced, and a molded product with few voids tends to be obtained, which is preferable.
The imidization ratio indicates the ratio of imide bonds in the main chain of polyimide, and can be determined by a conventionally known method, for example, an NMR method, an IR method, a titration method, or the like.

[Polyimide structure]
The structure of the polyimide of the present invention is not particularly limited, but has a unit derived from a tetracarboxylic dianhydride (tetracarboxylic acid residue) and a unit derived from a diamine compound and / or a diisocyanate compound (diamine residue).
Here, in the present invention, the tetracarboxylic acid residue contained in the polyimide and the functional group amount contained in the diamine residue satisfy the above-mentioned substituent amount I, substituent amount II and the substituent amount. Select the type and set the content ratio.

<Unit derived from tetracarboxylic dianhydride (tetracarboxylic acid residue)>
The tetracarboxylic dianhydride containing the tetracarboxylic acid residue contained in the polyimide of the present invention is not particularly limited. The tetracarboxylic dianhydride includes an aliphatic tetracarboxylic dianhydride (the aliphatic tetracarboxylic dianhydride includes an alicyclic tetracarboxylic dianhydride and a chain aliphatic tetracarboxylic dianhydride). ), Aromatic tetracarboxylic dianhydride and the like. One of these tetracarboxylic dianhydrides may be used alone, or two or more thereof may be used in any ratio and combination.

(Alicyclic tetracarboxylic dianhydride)
Examples of the alicyclic tetracarboxylic dianhydride include 3,3', 4,4'-biscyclohexanetetracarboxylic dianhydride, 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1 , 2,3,4-cyclopentanetetracarboxylic dianhydride, 1,2,4,5-cyclohexanetetracarboxylic dianhydride, 1,2,3,4-tetramethyl-1,2,3,4 -Cyclobutanetetracarboxylic dianhydride, 5- (2,5-dioxotetrahydrofuryl) -3-methyl-3-cyclohexane-1,2-dicarboxylic dianhydride, tricyclo [6.4.0.02,7 ] Dodecane-1,8: 2,7-tetracarboxylic dianhydride, bicyclo [2.2.2] Oct-7-ene-2,3,5,6-tetracarboxylic dianhydride, 4-( Examples thereof include 2,5-dioxo tetrahydrofuran-3-yl) -1,2,3,4-tetrahydronaphthalene-1,2-dicarboxylic dianhydride.

(Chain aliphatic tetracarboxylic dianhydride)
Examples of the chain aliphatic tetracarboxylic dianhydride include ethylenetetracarboxylic dianhydride, butanetetracarboxylic dianhydride, meso-butane-1,2,3,4-tetracarboxylic dianhydride and the like. Can be mentioned.

(Aromatic tetracarboxylic dianhydride)
Examples of the aromatic tetracarboxylic acid dianhydride include tetracarboxylic acid dianhydride having one aromatic ring in one molecule, tetracarboxylic acid dianhydride having two or more independent aromatic rings in one molecule, and 1 Examples thereof include tetracarboxylic acid dianhydride having a condensed aromatic ring in the molecule.

Among these, tetracarboxylic dianhydride having one aromatic ring in one molecule or tetracarboxylic dianhydride having one aromatic ring in one molecule tends to be easy to control the viscosity at the time of production, improve solvent solubility, and improve coating flexibility. A tetracarboxylic dianhydride having two or more independent aromatic rings in one molecule is preferable, and a tetracarboxylic dianhydride having two or more independent aromatic rings in one molecule is particularly preferable.

Examples of the tetracarboxylic dianhydride having one aromatic ring in one molecule include pyromellitic dianhydride, 1,2,3,4-benzenetetracarboxylic dianhydride and the like.

Examples of the tetracarboxylic dianhydride having two or more independent aromatic rings in one molecule include 1,1-bis (2,3-dicarboxyphenyl) ethanedianhydride and bis (2,3-di). Carboxyphenyl) methane dianhydride, bis (3,4-dicarboxyphenyl) methane dianhydride, 3,3', 4,4'-biphenyltetracarboxylic dianhydride, 2,2-bis (3,4) -Dicarboxyphenyl) propane dianhydride, 2,2-bis (2,3-dicarboxyphenyl) propane dianhydride, bis (3,4-dicarboxyphenyl) ether dianhydride, bis (2,3-) Dicarboxyphenyl) ether dianhydride, 3,3', 4,4'-benzophenonetetracarboxylic dianhydride, 2,2', 3,3'-benzophenonetetracarboxylic dianhydride, 4,4'- Oxydiphthalic dianhydride, 4,4- (p-phenylenedioxy) diphthalic dianhydride, 4,4- (m-phenylenedioxy) diphthalic dianhydride, 2,2', 6,6'- Examples thereof include biphenyltetracarboxylic dianhydride.

Examples of the tetracarboxylic dianhydride having a condensed aromatic ring in one molecule include 1,2,5,6-naphthalenedicarboxylic dianhydride, 1,4,5,8-naphthalenedicarboxylic dianhydride, 2, 3,6,7-naphthalenedicarboxylic dianhydride, 3,4,9,10-perylenetetracarboxylic dianhydride, 2,3,6,7-anthracenetetracarboxylic dianhydride, 1,2,7 , 8-phenanthrenetetracarboxylic dianhydride and the like.

(Other tetracarboxylic dianhydrides)
Examples of the tetracarboxylic dianhydride include silicone-based tetracarboxylic dianhydride and, for example, 2,2-bis (3,4-dicarboxyphenyl) -1,1,1,3,3,3. -Hexafluoropropane dianhydride (also known as 4,4'-(hexafluoroisopropyridene) -diphthalic acid dianhydride), 2,2-bis (2,3-dicarboxyphenyl) -1,1,1, 3,3,3-Hexafluoropropane dianhydride, 2,2'-bis (trifluoromethyl) -4,4', 5,5'-biphenyltetracarboxylic dianhydride, 4,4'-(hexa) Fluorotrimethylene) diphthalic dianhydride, 4,4'-(octafluorotetramethylene) diphthalic dianhydride, 2,2'-bis (trifluoromethyl) -4,4', 5,5'-biphenyl Tetetracarboxylic dianhydride, 4,4'-(hexafluorotrimethylethylene) diphthalic acid dianhydride, 4,4'-(octafluorotetramethylene) diphthalic acid dianhydride, 2,2-bis (3,4) −Dicarboxyphenyl) -1,1,1,3,3,3-hexafluoropropanedianhydride, 2,2-bis (2,3-dicarboxyphenyl) -1,1,1,3,3 3-Hexafluoropropanedianhydride, 2,2-bis (3,4-dicarboxyphenyl) -1,1,1,3,3,3-hexafluoropropanedianhydride, 2,2-bis (2) , 3-Dicarboxyphenyl) -1,1,1,3,3,3-Hexafluoropropanedianhydride and other tetracarboxylic dianhydrides containing a fluorine atom can also be used.

The tetracarboxylic dianhydride that induces the tetracarboxylic acid residue contained in the polyimide of the present invention may contain only one type or two or more types, but the solvent solubility of the polyimide is high. For improvement, it is preferable to contain a tetracarboxylic acid residue derived from an aliphatic tetracarboxylic dianhydride, and more preferably to contain a tetracarboxylic acid residue derived from an alicyclic tetracarboxylic dianhydride.

The ratio of the tetracarboxylic acid residue derived from the aliphatic tetracarboxylic acid dianhydride to the total tetracarboxylic acid residue contained in the polyimide of the present invention is not particularly limited, but is usually preferably 10 mol% or more, preferably 25 mol% or more. Is more preferable, and 40 mol% or more is further preferable. There is no upper limit and it may be 100 mol%. When the ratio of the tetracarboxylic acid residue derived from the tetracarboxylic acid dianhydride is at least the above lower limit, the solubility in the solvent is high, which is preferable.

<Unit derived from diamine compound>
Examples of the diamine compound for inducing the diamine residue contained in the polyimide of the present invention include aromatic diamine compounds and aliphatic diamine compounds (aliphatic diamine compounds include alicyclic diamine compounds and chain aliphatic diamine compounds). Can be mentioned. One of these diamine compounds may be used alone, or two or more of these diamine compounds may be used in any ratio and combination.

(Aromatic diamine compound)
Examples of the aromatic diamine compound include a diamine compound having one aromatic ring in one molecule, a diamine compound having a condensed aromatic ring in one molecule, and a diamine compound having two or more independent aromatic rings in one molecule. Can be mentioned.

Examples of the diamine compound having one aromatic ring in one molecule include 1,4-phenylenediamine, 1,2-phenylenediamine, 1,3-phenylenediamine, 4-fluoro-1,2-phenylenediamine, and the like. 4-Fluoro-1,3-phenylenediamine, 3-trifluoromethyl-1,5-phenylenediamine, 4-trifluoromethyl-1,5-phenylenediamine, 4-trifluoromethyl-1,2-phenylenediamine, Examples thereof include 2-trifluoromethyl-1,4-phenylenediamine and 2,5-dimethyl-1,4-phenylenediamine.

Examples of the diamine compound having a condensed aromatic ring in one molecule include 4,4'-(9-fluorenylidene) dianiline, 2,7-diaminofluorene, 1,5-diaminonaphthalene, and 3,7-diamino-2,8-. Examples thereof include dimethyldibenzothiophene 5,5-dioxide.

Diamine compounds having two or more independent aromatic rings in one molecule include 4,4'-(biphenyl-2,5-diylbisoxy) bisaniline and 4,4'-diamino-3, which have a biphenyl structure. , 3'-dimethylbiphenyl, 4,4'-diamino-2,2'-dimethylbiphenyl (also known as 3,3'-dimethylbenzidine or m-trizine), 4,4'-bis (4-aminophenoxy) biphenyl , 4,4'-diamino-2,2'-dimethoxybiphenyl, 4,4'-diamino-3,3'-dimethoxybiphenyl, 4,4'-diamino-2,2'-dichlorobiphenyl, 4,4' -Diamino-3,3'-dichlorobiphenyl, 2,2'-bis (trifluoromethyl) -4,4'-diaminobiphenyl, 4,4'-diamino-2-methyl-2'-trifluoromethylbiphenyl, etc. , 4,4-diaminozensanilide, 4,4'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 1,4-bis (4-aminophenoxy) benzene, 1,4, in which aromatic rings are linked to each other by a linker. 3-Bis (4-aminophenoxy) benzene, bis (4- (4-aminophenoxy) phenyl) sulfone, 2,2-bis (4- (4-aminophenoxy) phenyl) propane, bis (4- (3- (3-)3-) Aminophenoxy) phenyl) sulfone, 1,3-bis (4-aminophenoxy) neopentane, 4,4'-diaminodiphenylsulfone, 3,3′-diaminodiphenylsulfone, 4,4′-diaminodiphenylsulfide, N-( 4-Aminophenoxy) -4-aminobenzamine, bis (3-aminophenyl) sulfone, norbornandiamine, bis (4- (4-aminophenoxy) phenyl) sulfone, bis (4- (3-aminophenoxy) phenyl) Sulfone, 4,4'-diaminodiphenyl sulfone, 3,3'-diaminodiphenyl sulfone, N- [4- (4-aminophenoxy) phenyl] -4-aminobenzamide, 4,4-diaminobenzanilide, bis (3) 2,2-bis [4- (4-aminophenoxy) phenyl] hexafluoropropane, 2,2-bis [4- {4-amino-2- (trifluoro), having a fluorine atom such as −aminophenyl) sulfone Methyl) phenoxy} phenyl] hexafluoropropane, 2,2-bis (3-amino-4-methylphenyl) hexafluoropropane, 2,2-bis (3-amino) -4-Hydroxyphenyl) hexafluoropropane, 2,2-bis (4-aminophenyl) hexafluoropropane, 2,2-bis (3-aminophenyl) hexafluoropropane, 2,2-bis {4- (4) -Aminophenoxy) -3,5-dibromophenyl} Hexafluoropropane and the like.

Among them, a diamine compound having a biphenyl structure or a diamine compound in which aromatic rings are linked by a linker is preferable, and a diamine compound having a biphenyl structure is more preferable, because the elastic modulus tends to be high.

(Aliphatic diamine compound)
Examples of the aliphatic diamine compound include an alicyclic diamine compound and a chain aliphatic diamine compound.

Examples of the alicyclic diamine compound include 1,3-bis (aminomethyl) cyclohexane, 1,4-bis (aminomethyl) cyclohexane, 1,4-diaminocyclohexane, and 4,4'-methylenebis (cyclohexylamine). Examples thereof include 4,4'-methylenebis (2-methylcyclohexylamine).

Examples of the chain aliphatic diamine compound include 1,2-ethylenediamine, 1,2-diaminopropane, 1,3-diaminopropane, 1,4-diaminobutane, 1,6-hexamethylenediamine, and 1,5-. Examples thereof include diaminopentane, 1,10-diaminodecane, 1,2-diamino-2-methylpropane, 2,3-dimethyl-2,3-butanediamine, 2-methyl-1,5-diaminopentane and the like.

<Unit derived from diisocyanate compound>
Examples of the diisocyanate compound for inducing the diamine residue contained in the polyimide of the present invention include aromatic diisocyanate compounds and aliphatic diisocyanate compounds. One of these diisocyanate compounds may be used alone, or two or more of these diisocyanate compounds may be used in any ratio and combination.

Examples of the aromatic diisocyanate compound include 4,4'-diisocyanato-3,3'-dimethylbiphenyl, 2,2-bis (4-isocyanatophenyl) hexafluoropropane, and 4,4'-diisocyanato-3,3. '-Dimethyldiphenylmethane, 1,5-diisocyanatonaphthalene, 4,4'-methylenediphenyl diisocyanate, 1,3-phenylene diisocyanate, 1,4-phenylenediisocyanate, 1,3-bis (isocyanatomethyl) ) Benzene, toluene diisocyanate and the like.

Examples of the aliphatic diisocyanate compound include 1,3-bis (isocyanatomethyl) cyclohexane, hexamethylene diisocyanate, and isophorone diisocyanate.

The diamine compound and diisocyanate compound for inducing the diamine residue contained in the polyimide of the present invention may be only one kind or may contain two or more kinds, but the heat resistance of the obtained polyimide tends to be high. Therefore, an aromatic diamine compound is preferable, a diamine compound having a condensed aromatic ring in one molecule, and a diamine compound having two or more independent aromatic rings in one molecule are more preferable.

The ratio of the unit derived from the aromatic diamine compound to the total diamine residue contained in the polyimide of the present invention is not particularly limited, but is usually preferably 10 mol% or more, more preferably 20 mol% or more, still more preferably 40 mol% or more. .. There is no upper limit and it may be 100 mol%. When the ratio of the unit derived from the aromatic diamine compound is at least the above lower limit, the heat resistance is increased and the production is facilitated, which is preferable.

The ratio of the tetracarboxylic acid residue and the diamine residue contained in the polyimide can be determined by analyzing the composition of the raw material monomer by NMR, solid-state NMR, IR or the like. Further, it can be obtained by gas chromatography (GC), ¹ H-NMR, ¹³ C-NMR, two-dimensional NMR, mass spectrometry, etc. after being dissolved in alkali.

[Molecular weight of polyimide]
The molecular weight of the polyimide of the present invention is not particularly limited, but the polystyrene-equivalent number average molecular weight (Mn) is preferably 3000 or more, more preferably 5000 or more, and further preferably 8000 or more. On the other hand, this molecular weight is preferably 100,000 or less, more preferably 80,000 or less, still more preferably 60,000 or less. When the number average molecular weight (Mn) of the polyimide is in this range, the solubility, the solution viscosity, and the like are in a range that can be easily handled by ordinary equipment, which is preferable.
The polystyrene-equivalent number average molecular weight (Mn) of the polyimide of the present invention can be determined by gel permeation chromatography (GPC).

The mass average molecular weight (Mw) of the polyimide of the present invention is preferably 6000 or more, more preferably 8000 or more, and further preferably 10000 or more. On the other hand, it is preferably 300,000 or less, more preferably 200,000 or less, and further preferably 180,000 or less. When the mass average molecular weight (Mw) of the polyimide is in this range, the solubility, the solution viscosity, and the like are in the range that can be easily handled by ordinary equipment, which is preferable.
The mass average molecular weight (Mw) of the polyimide of the present invention can be measured by the same method as the number average molecular weight (Mn).

The molecular weight distribution (PDI: Mw / Mn) of the polyimide of the present invention is usually 1 or more, preferably 1,1 or more, and more preferably 1.2 or more. On the other hand, Mw / Mn is usually 20 or less, preferably 15 or less, and more preferably 10 or less. When Mw / Mn is in this range, the uniformity and smoothness of the obtained molded product tend to be excellent.

[Glass transition temperature of polyimide]
The glass transition temperature (Tg) of the polyimide of the present invention is not particularly limited, but is preferably 150 ° C. or higher, more preferably 180 ° C. or higher, still more preferably 200 ° C. or higher. On the other hand, Tg is preferably 400 ° C. or lower, more preferably 380 ° C. or lower, and even more preferably 360 ° C. or lower. When the glass transition temperature (Tg) of polyimide is in this range, the heat resistance of the obtained molded product is improved, and the residual solvent in low-load process molding such as suppression of molding temperature and molding under air is reduced. Tend to do.
The glass transition temperature (Tg) is measured as the peak of α relaxation in the dynamic viscoelasticity measurement, as described in the section of Examples described later.

[Polyimide particles]
Generally, the shape of the resin includes a fibrous shape, a lump shape, a particle shape, and the like. The shape of the polyimide of the present invention is usually not particularly limited, but it is preferably in the form of particles because the solubility and dispersibility tend to be improved (hereinafter, the polyimide in the form of particles may be referred to as "polyimide particles". is there.).
The polyimide can be made into particles by a conventionally known method, and the granulation method is not particularly limited. For example, a method obtained by dropping a diluted polyimide solution as droplets in a poor solvent and stirring the mixture, or spraying. Examples thereof include a method of spraying a poor solvent through a nozzle, a method of spraying and drying through a spray nozzle, and the like.

The particle size of the polyimide particles of the present invention is usually not particularly limited, but is preferably 1 μm or more, more preferably 5 μm or more, still more preferably 20 μm or more, particularly preferably 50 μm or more, preferably 2000 μm or less, more preferably 1800 μm. Below, it is more preferably 1500 μm or less, and particularly preferably 1000 μm or less. When the particle size is at least the above lower limit, the amount of scattering during handling can be suppressed and the environmental load can be reduced. Further, when the particle size is not more than the above upper limit value, the solubility and dispersibility of the polyimide particles at the time of preparing the polyimide solution tend to be good.
The particle size of the polyimide particles can be determined by a conventionally known method, for example, using a particle size distribution meter.

[Polyimide manufacturing method]
The method for producing the polyimide of the present invention is not particularly limited, and the polyimide can be produced by a conventionally known method. For example, a method of producing a polyimide precursor from a tetracarboxylic acid dianhydride and a diamine compound and / or a diisocyanate compound and imidizing the polyimide precursor to obtain a polyimide, or a polyimide directly from a tetracarboxylic acid dianhydride and a diamine compound and / or a diisocyanate compound. There is a way to manufacture.
Hereinafter, the method for producing the polyimide of the present invention will be described by exemplifying the case where a tetracarboxylic dianhydride and a diamine compound are used. However, a diisocyanate compound may be used instead of the diamine compound, and the diamine compound and the diamine compound May be used together.

<Method of producing polyimide via polyimide precursor>
When the polyimide is produced via the polyimide precursor, the polyimide precursor can be obtained, for example, by reacting a tetracarboxylic dianhydride with a diamine compound in a solvent.
In this case, the order of addition and the method of addition of the tetracarboxylic dianhydride and the diamine compound are not particularly limited. For example, a polyimide precursor can be obtained by sequentially adding a diamine compound and a tetracarboxylic dianhydride to a solvent and stirring at an appropriate temperature.

The amount of tetracarboxylic dianhydride is usually 0.7 mol or more, preferably 0.8 mol or more, and usually 1.3 mol or less, preferably 1.2 mol or less, relative to 1 mol of the diamine compound. is there. By setting the amount of tetracarboxylic dianhydride in such a range, the yield of the obtained polyimide precursor tends to be improved.

The concentrations of the tetracarboxylic dianhydride and the diamine compound in the reaction solution can be appropriately set according to the reaction conditions and the viscosity of the obtained polyimide precursor.

The total concentration of the tetracarboxylic dianhydride and the diamine compound is not particularly limited, but is usually 1% by mass or more, preferably 5% by mass or more, and usually 70% by mass or less, preferably 50% by mass, based on the total amount of the reaction solution. It is mass% or less. If the concentrations of the tetracarboxylic dianhydride and the diamine compound in the reaction solution are not too low, the molecular weight tends to be extended, and if the concentration is not too high, the viscosity of the reaction solution does not become too high and stirring is performed. It tends to be easier.

The temperature at which the tetracarboxylic dianhydride and the diamine compound are reacted in the solvent is not particularly limited as long as the reaction proceeds, but is usually 0 ° C. or higher, preferably 20 ° C. or higher, and usually 120 ° C. or lower. It is preferably 100 ° C. or lower.
The reaction time is usually 1 hour or more, preferably 2 hours or more, usually 100 hours or less, preferably 42 hours or less.
By carrying out under such conditions, a polyimide precursor tends to be obtained at low cost and in good yield.
The pressure during the reaction may be normal pressure, pressurization or depressurization.
The atmosphere may be under air or under an inert atmosphere.

The solvent used when reacting the tetracarboxylic dianhydride and the diamine compound, that is, the production solvent is not particularly limited. For example, hydrocarbon solvents such as hexane, cyclohexane, heptane, benzene, toluene, xylene, mecitylene, anisole; halogenation of carbon tetrachloride, methylene chloride, chloroform, 1,2-dichloroethane, chlorobenzene, dichlorobenzene, fluorobenzene and the like. Hydrocarbon solvent; ether solvent such as diethyl ether, tetrahydrofuran, 1,4-dioxane, methoxybenzene; ketone solvent such as acetone, methyl ethyl ketone, cyclohexanone, methyl isobutyl ketone; ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene Glycol-based solvents such as glycol dimethyl ether, diethylene glycol dimethyl ether and propylene glycol monomethyl ether acetate; amide-based solvents such as N, N-dimethylformamide, N, N-dimethylacetamide and N-methyl-2-pyrrolidone; Solvents; heterocyclic solvents such as pyridine, picolin, lucidine, quinoline, isoquinoline; phenolic solvents such as phenol and cresol; lactone solvents such as γ-butyrolactone, γ-valerolactone, δ-valerolactone; and the like. .. One of these solvents may be used alone, or two or more of these solvents may be used in any ratio and combination.

In the present invention, among these production solvents, it is particularly preferable to use N-methyl-2-pyrrolidone (NMP) and N, N-dimethylacetamide (DMAc).

The obtained polyimide precursor may be used as it is for the next imidization, or may be added to a poor solvent to precipitate it in a solid state before use.

The poor solvent to be used is not particularly limited and may be appropriately selected depending on the type of polyimide precursor, but an ether solvent such as diethyl ether and diisopropyl ether; a ketone solvent such as acetone, methyl ethyl ketone, isobutyl ketone and methyl isobutyl ketone; methanol, Alcohol-based solvents such as ethanol and isopropyl alcohol; and the like. Above all, an alcohol solvent is preferable because a precipitate can be efficiently obtained, a boiling point is low, and drying tends to be easy. One of these solvents may be used alone, or two or more of these solvents may be used in any ratio and combination.

(Immidization of polyimide precursor)
A polyimide can be obtained by dehydrating and cyclizing the polyimide precursor obtained by the above method or the like in the presence of a solvent. The imidization can be carried out by using any conventionally known method, and examples thereof include thermal imidization in which thermal cyclization is performed, chemical imidization in which chemical cyclization is performed, and the like. These imidization reactions may be carried out individually or in combination of two or more.

<Heating imidization>
Examples of the solvent for imidizing the polyimide precursor include the same solvent used in the reaction for obtaining the polyimide precursor. The solvent used for producing the polyimide precursor and the solvent used for producing the polyimide may be the same or different.
In this case, the water produced by imidization inhibits the ring closure reaction and may be discharged from the system. The concentration of the polyimide precursor at the time of the imidization reaction is not particularly limited, but is usually 1% by mass or more, preferably 5% by mass or more, and usually 70% by mass or less, preferably 40% by mass or less. By performing in this range, it is possible to produce with a solution viscosity that has high production efficiency and is easy to produce.

The reaction temperature for imidization is not particularly limited, but is usually 50 ° C. or higher, preferably 80 ° C. or higher, more preferably 100 ° C. or higher, and usually 300 ° C. or lower, preferably 280 ° C. or lower, further preferably 250 ° C. or lower. .. It is preferable to carry out in this range because the imidization reaction proceeds efficiently and reactions other than the imidization reaction tend to be suppressed.
The pressure during the reaction may be normal pressure, pressurization, or depressurization.
The atmosphere may be under air or under an inert atmosphere.

Further, as an imidization accelerator for promoting imidization, a compound having a function of enhancing nucleophile and electrophile can be added. Specifically, for example, trimethylamine, triethylamine, tripropylamine, tributylamine, triethanolamine, N, N-dimethylethanolamine, N, N-diethylethanolamine, triethylenediamine, N-methylpyrrolidin, N-ethylpyrrolidin. , N-Methylpiperidin, N-ethylpiperidine, imidazole, pyridine, quinoline, isoquinoline and other tertiary amine compounds; acetic acid, 4-hydroxyphenylacetic acid, 3-hydroxybenzoic acid, N-acetylglycine, N-benzoylglycine and the like. Carboxylic acid compounds; polyvalent phenolic compounds such as 3,5-dihydroxyacetophenone, methyl 3,5-dihydroxybenzoate, pyrogallol, methyl gallate, ethyl gallate, naphthalene-1,6-diol; 2-hydroxypyridine, 3-hydroxy Pyridine, 4-hydroxypyridine, 4-pyridinemethanol, N, N-dimethylaminopyridine, nicotine aldehyde, isonicotin aldehyde, picolin aldehyde, picolin aldehyde oxime, nicotine aldehyde oxime, isonicotin aldehyde oxime, ethyl picolinate, ethyl nicotinate , Ethyl isonicotinate, nicotine amide, isonicotinamide, 2-hydroxynicotinic acid, 2,2'-dipyridyl, 4,4'-dipyridyl, 3-methylpyridazine, quinoline, isoquinolin, phenanthroline, 1,10-phenanthroline, Heterocyclic compounds such as imidazole, benzimidazole, 1,2,4-triazole; and the like.

Of these, at least one selected from the group consisting of tertiary amine compounds, carboxylic acid compounds and heterocyclic compounds is preferable, and at least one selected from the group consisting of triethylamine, imidazole and pyridine controls the reaction rate. It is more preferable because it tends to be easy. One of these compounds may be used alone, or two or more thereof may be used in any ratio and combination.

The amount of the imidization accelerator used is usually 0.01 mol% or more, preferably 0.1 mol% or more, and further preferably 1 mol% or more, based on the carboxyl group of the polyimide precursor. Further, it is preferably 50 mol% or less, and more preferably 10 mol% or less. When the amount of the imidization accelerator used is within the above range, the imidization reaction tends to proceed efficiently.
Further, the timing of adding the imidization accelerator can be appropriately adjusted, and may be before the start of heating or during heating. Further, it may be added in a plurality of times.

<Chemical imidization>
A polyimide can be obtained by chemically imidizing a polyimide precursor with a dehydration condensing agent in the presence of a solvent.

Examples of the solvent used for chemical imidization include the same solvents as those used for the reaction for obtaining the polyimide precursor.

Examples of the dehydration condensing agent include N, N-2 substituted carbodiimides such as N, N-dicyclohexylcarbodiimide and N, N-diphenylcarbodiimide; acid anhydrides such as acetic anhydride and trifluoroacetic anhydride; thionyl chloride, tosyl chloride and the like. Chloride; acetyl chloride, acetyl bromide, propionyl iodide, acetyl fluoride, propionyl chloride, propionyl bromide, propionyl iodide, propionyl fluoride, isobutyryl chloride, isobutyryl bromide, isobutyryl iodide, isobuchi Lilfluoride, n-butyryl chloride, n-butyryl bromide, n-butyryl iodide, n-butyryl fluoride, mono-, di-, tri-chloroacetyl chloride, mono-, di-, tri- Bromoacetyl chloride, mono-, di-, tri-iodoacetyl chloride, mono-, di-, tri-fluoroacetyl chloride, chloroacetic anhydride, phenylphosphonic dichloride, thionyl chloride, thionyl bromide, thionyliodide, thionylfluo Halogen compounds such as rides; phosphorus compounds such as phosphorus trichloride, triphenyl phosphite, cyanide diethyl phosphate; and the like.

Of these, acid anhydrides and halogenated compounds are preferable, and acid anhydrides are particularly preferable because the imidization reaction tends to proceed efficiently. One of these compounds may be used alone, or two or more thereof may be used in any ratio and combination.

The amount of these dehydration condensing agents used is usually 0.1 mol or more, preferably 0.2 mol or more, and usually 1.6 mol or less, preferably 1.0 mol or less, with respect to 1 mol of the polyimide precursor. By setting the amount of the dehydration condensing agent used within this range, imidization can be performed efficiently.

The concentration of the polyimide precursor in the reaction solution during the imidization reaction is not particularly limited, but is usually 1% by mass or more, preferably 5% by mass or more, and usually 70% by mass or less, preferably 40% by mass or less. .. Within this range, the production efficiency can be increased, and the solution viscosity tends to be easy to produce.

The imidization reaction temperature is not particularly limited, but is usually 0 ° C. or higher, preferably 10 ° C. or higher, and more preferably 20 ° C. or higher. Further, it is usually 150 ° C. or lower, preferably 130 ° C. or lower, and more preferably 100 ° C. or lower. It is preferable to carry out in this range because the imidization reaction tends to proceed efficiently. Further, it is preferable because side reactions other than the imidization reaction are suppressed.
The pressure during the reaction may be normal pressure, pressurization or depressurization.
The atmosphere may be under air or under an inert atmosphere.

Further, as a catalyst for promoting imidization, an imidization accelerator such as the above-mentioned tertiary amine compound can be added in the same manner as for heat imidization.

<Method of producing polyimide from tetracarboxylic dianhydride and diamine compound>
Polyimide can be directly obtained from a tetracarboxylic dianhydride and a diamine compound by using a conventionally known method. This method involves the synthesis and imidization of the poimide precursor, and the imidization without stopping the reaction or isolating the precursor.

The order and method of adding the tetracarboxylic dianhydride and the diamine compound are not particularly limited. For example, the temperature at which the tetracarboxylic dianhydride and the diamine compound are added in order to the solvent and the reaction until imidization proceeds. Polyimide can be obtained by stirring with.

The amount of the diamine compound is usually 0.7 mol or more, preferably 0.8 mol or more, and usually 1.3 mol or less, preferably 1.2 mol or less, with respect to 1 mol of the tetracarboxylic dianhydride. By setting the amount of the diamine compound in such a range, the yield of the obtained polyimide tends to be improved.

The concentrations of the tetracarboxylic dianhydride and the diamine compound in the reaction solution can be appropriately set according to each condition and the viscosity during polymerization.
The total concentration of the tetracarboxylic dianhydride and the diamine compound in the reaction solution is not particularly set, but is usually 1% by mass or more, preferably 5% by mass or more, and usually 70% by mass or less, preferably 40% by mass. It is as follows. When the concentration in the reaction solution is in an appropriate range, the molecular weight tends to be extended and stirring tends to be easy.

Examples of the solvent used in this reaction include the same solvents as those used in the reaction for obtaining the polyimide precursor.

Further, when the polyimide is obtained from the tetracarboxylic acid dianhydride and the diamine compound, heating imidization and / or chemical imidization can be adopted as in the case of obtaining the polyimide from the polyimide precursor, and heating in this case can be adopted. The reaction conditions for imidization and chemical imidization are the same as described above.

The obtained polyimide may be used as it is, or may be used by adding it to a poor solvent to precipitate the polyimide in a solid state and then redissolving it in another solvent.

The poor solvent at this time is not particularly limited and may be appropriately selected depending on the type of polyimide. For example, an ether solvent such as diethyl ether and diisopropyl ether; a ketone solvent such as acetone, methyl ethyl ketone, isobutyl ketone and methyl isobutyl ketone; Alcohol-based solvents such as methanol, ethanol, and isopropyl alcohol; and the like. Above all, an alcohol solvent such as isopropyl alcohol is preferable because a precipitate can be efficiently obtained, the boiling point is low, and drying tends to be easy. One of these solvents may be used alone, or two or more of these solvents may be used in any ratio and combination.

[Methylene chloride composition]
The methylene chloride composition of the present invention contains the polyimide of the present invention and methylene chloride, and is characterized in that the content of a solvent having a boiling point of 150 ° C. or higher is 5000 ppm or less.
Here, the solvent having a boiling point of 150 ° C. or higher is as described above.

When the content of the solvent having a boiling point of 150 ° C. or higher of the methylene chloride composition of the present invention exceeds 5000 ppm, for example, when a polyimide film is formed using this methylene chloride composition, a polyimide film having excellent bending resistance and the like can be obtained. I can't get it. The content of the solvent having a boiling point of 150 ° C. or higher is preferably 3000 ppm or less, particularly preferably 1000 ppm or less. The lower limit of the content of the solvent having a boiling point of 150 ° C. or higher in the methylene chloride composition of the present invention is not particularly limited.

In order to obtain a methylene chloride composition having a boiling point of 150 ° C. or higher and a solvent content of 150 ° C. or higher, a polyimide having a boiling point of 150 ° C. or higher and a low content of a solvent may be used. The methylene chloride composition of the present invention can be prepared. A polyimide having a boiling point of 150 ° C. or higher and a low content of a solvent can be obtained by controlling the amounts of substituents I and II described above.

The content of polyimide in the methylene chloride composition of the present invention is not particularly limited and can be appropriately adjusted according to the intended use. For example, in the case of a polyimide film film forming application, the content is 5% by mass or more. Is more preferable, 10% by mass or more is more preferable, 70% by mass or less is preferable, and 60% by mass or less is more preferable. When the polyimide content is in this range, film formation and handling in ordinary equipment are easy, which is preferable.

The methylene chloride composition of the present invention may contain components other than polyimide and methylene chloride, and the other components may include a polyimide composition used for producing a polyimide film described later. Examples of other components include those exemplified.
The methylene chloride content of the methylene chloride composition of the present invention is usually 30% by weight or more, and the total content of the polyimide and methylene chloride of the present invention is usually 90% by weight or more.

Examples of the solvent other than methylene chloride that can be used in the methylene chloride composition include hydrocarbon solvents such as hexane, cyclohexane, heptane, benzene, toluene, xylene, mesitylene, and anisole; N, N-dimethylformamide, N, Amid solvents such as N-dimethylacetamide and N-methyl-2-pyrrolidone; Aproton solvents such as dimethyl sulfoxide; Ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, propylene glycol monomethyl ether acetate Glycol-based solvent such as; Of these, N, N-dimethylformamide, N, N-dimethylacetamide, and N-methyl-2-pyrrolidone are particularly preferable. One of these solvents may be used alone, or two or more of these solvents may be used in any ratio and combination.
When the methylene chloride composition of the present invention contains a solvent other than methylene chloride, the content is not particularly limited, but the solvent other than methylene chloride is preferably 5% by mass or less, more preferably 1 with respect to the amount of methylene chloride. It is mass% or less, more preferably 0.5 mass% or less.

[Polyimide film]
The polyimide film of the present invention contains the polyimide of the present invention, and can be produced, for example, by forming a film by a coating method using a polyimide composition in which the polyimide of the present invention is dissolved in a solvent.

The solvent used here is not particularly limited, and the solvent used at the time of production may be used as it is, or a new solvent may be added. Among these, it is preferable to use a solvent having a boiling point of 100 ° C. or lower. Further, in the case of a mixed solvent, it is preferable to contain 50% by mass or more of a solvent having a boiling point of 100 ° C. or lower.

Examples of the solvent used include methanol (boiling point 64.5 ° C.), ethanol (boiling point 78.3 ° C.), n-propanol (boiling point 97.2 ° C.), i-propanol (boiling point 82.2 ° C.), and t-butyl. Alcohol-based solvents such as alcohol (boiling point 82.3 ° C), 1,2-diethoxyethane (boiling point 84.5 ° C), diethyl ether (boiling point 34.4 ° C), diisopropyl ether (boiling point 68.5 ° C), tetrahydrofuran Ether solvent such as (boiling point 66.0 ° C.), ester solvent such as ethyl acetate (boiling point 77.1 ° C.), ketone solvent such as acetone (boiling point 56.1 ° C.), methyl ethyl ketone (boiling point 79.6 ° C.) , Halogen-based solvents such as carbon tetrachloride (boiling point 76.6 ° C), chloroform (boiling point 61.2 ° C), methylene chloride (boiling point 39.6 ° C), 1,2-dichloroethane (boiling point 83.5 ° C), benzene (Boiling point 80.1 ° C), cyclohexane (boiling point 80.7 ° C), pentane (boiling point 36.1 ° C), hexane (boiling point 68.7 ° C) heptane (boiling point 98.4 ° C) and other hydrocarbon solvents, acetonitrile Examples thereof include nitrile solvents such as (boiling point 81.6 ° C.).

Among them, since the solubility of polyimide tends to be high, an ether solvent, an ester solvent, a ketone solvent or a halogen solvent is preferable, and an ester solvent, a ketone solvent, a halogen solvent, or a mixture thereof is more preferable.
As the polyimide composition, the methylene chloride composition of the present invention using methylene chloride as a solvent may be used.

The content of polyimide in the polyimide composition is not particularly limited and can be appropriately adjusted according to the production process and the like, but for example, it is preferably 5% by mass or more, and more preferably 10% by mass or more. It is preferable, and it is preferably 70% by mass or less, and more preferably 60% by mass or less. When the polyimide content is in this range, film formation and handling in ordinary equipment are easy, which is preferable.

The polyimide composition may contain other components in addition to the polyimide and the solvent.
Other components include, for example, surfactants, solvents, antioxidants, lubricants, colorants, stabilizers, UV absorbers, antistatic agents, flame retardants, plasticizers, mold release agents, leveling agents, defoamers. Agents and the like can be mentioned. In addition, if necessary, an inorganic filler or an organic filler such as powder, granular, plate, or fibrous may be blended as long as the object of the invention is not impaired.
These additive components may be added at any stage of any process for producing the polyimide precursor and / or the polyimide composition.

Among these components, it is preferable to include a surfactant and a leveling agent because the smoothness of the obtained polyimide film tends to be improved.

Examples of the leveling agent include silicone compounds and the like. The silicone-based compound is not particularly limited, and for example, polyether-modified siloxane, polyether-modified polydimethylsiloxane, polyether-modified hydroxyl group-containing polydimethylsiloxane, polyether-modified polymethylalkylsiloxane, polyester-modified polydimethylsiloxane, and polyester-modified hydroxyl group. Examples thereof include polydimethylsiloxane contained, polyester-modified polymethylalkylsiloxane, aralkyl-modified polymethylalkylsiloxane, highly polymerized silicone, amino-modified silicone, amino derivative silicone, phenyl-modified silicone, and polyether-modified silicone. One of these may be used alone, or two or more thereof may be used in any ratio and combination.

Examples of the surfactant include a cationic surfactant, an anionic surfactant, an amphoteric surfactant, a nonionic surfactant and the like.

Examples of the nonionic surfactant include the following, and one type or a plurality of nonionic surfactants may be used in combination.
Examples of the nonionic surfactant used in the present invention include ether type, ester type, ether ester type, polyhydric alcohol type, amide type, polymer type and the like.

Examples of the ether type include polyoxyalkylene alkyl ethers and the like, and examples thereof include polyoxyethylene ethers and polyoxypropylene ethers.
Examples of the polyoxyethylene ether include polyoxyethylene alkyl allyl ether, polyoxyethylene alkyl phenyl ether, polyoxyethylene polyoxypropylene glycol, polyoxyethylene alkyl amine, polyoxyethylene lauryl ether, polyoxyethylene oleyl ether, and polyoxy. Examples thereof include ethylene stearyl ether.

Examples of the ester type include sorbitan fatty acid ester, glycerin fatty acid ester, sucrose fatty acid ester, sucrose benzoic acid ester, sucrose derivative, and fatty acid ester.

Examples of the ether ester type include polyoxyethylene sorbitan fatty acid ester, polyoxyethylene sorbitol fatty acid ester, polyoxyethylene fatty acid ester, and polyoxyethylene hydrogenated castor oil ether.

Examples of the polyhydric alcohol type include alkyl glucosides and alkyl polyglucosides.
Examples of the amide type include alkylalkanolamides and the like.

Examples of the polymer type include polyvinylpyrrolidone, a polyalkylene polyamine alkylene oxide adduct, a polyalkylene polyimine alkylene oxide adduct, and the like.

These additives are preferably compatible with the polyimide and solvent of the present invention, and particularly preferably with methylene chloride. The compatibility is preferable because the pot life of the polyimide composition is improved and the appearance of the polyimide film tends to be improved.

The film forming method of the polyimide film using the above-mentioned polyimide composition is sometimes not limited, and examples thereof include a method of applying the polyimide composition to a substrate or the like.
Examples of the coating method include die coating, spin coating, dip coating, screen printing, spraying, casting method, method using a coater, coating method by spraying, dipping method, calendar method and salivation method. These methods can be appropriately selected depending on the coated area, the shape of the surface to be coated, and the like.

The method of volatilizing the solvent contained in the film formed by coating or the like is not particularly limited. Usually, the solvent is volatilized by heating the carrier substrate to which the composition is applied. The heating method is not particularly limited, and examples thereof include hot air heating, vacuum heating, infrared heating, microwave heating, and heating by contact using a hot plate / hot roll or the like.

As the heating temperature in the above case, a suitable temperature can be used depending on the type of solvent. The heating temperature is usually above the boiling point of the solvent, preferably above the boiling point of the solvent + 50 ° C, more preferably above the boiling point of the solvent + 100 ° C, more preferably below the boiling point of the usual solvent + 200 ° C, preferably below the boiling point of the solvent + 180 ° C, more preferably. Is the boiling point of the solvent + 150 ° C. or lower. When the heating temperature is in the above range, the solvent is sufficiently volatilized, which is preferable.

The polyimide film of the present invention can be obtained, for example, by applying a polyimide composition containing the polyimide of the present invention and a solvent to a support, heating the support, and peeling the film from the support.
The method of peeling the polyimide film from the support is not particularly limited, but a physical peeling method or a laser peeling method is preferable in that the polyimide film can be peeled off without impairing the performance of the film or the like.

Examples of the method of physically peeling include a method of obtaining a polyimide film by cutting off the peripheral edge of a laminate made of a polyimide film / support, a method of sucking the peripheral edge portion to obtain a polyimide film, and a method of fixing the peripheral edge and supporting a base material. A method of obtaining a polyimide film by moving the film can be mentioned.

The thickness of the polyimide film of the present invention is usually 1 μm or more, preferably 2 μm or more, while it is usually 300 μm or less, preferably 200 μm or less. When the thickness is 1 μm or more, the polyimide film can obtain sufficient strength and can be obtained as a self-supporting film, and the handleability tends to be improved. Further, by setting the thickness to 300 μm or less, the uniformity of the film tends to be easily ensured.

The performance required for the polyimide film of the present invention depends on the application, but it is preferable to have the following mechanical strength.

The tensile strength of the polyimide film of the present invention is not particularly limited, but is usually 50 MPa or more, preferably 70 MPa or more, more preferably 100 MPa or more, still more preferably 150 MPa or more in measurement at 23 ° C. and 50% humidity. It is usually 400 MPa or less, preferably 300 MPa or less.

The tensile elastic modulus of the polyimide film of the present invention is not particularly limited, but is usually 1500 MPa or more, preferably 1800 MPa or more, more preferably 2000 MPa or more, and particularly preferably 3000 MPa or more in measurement at 23 ° C. and 50% humidity. , Usually 20 GPa or less, preferably 10 GPa or less.

The tensile elongation of the polyimide film of the present invention is not particularly limited, but is usually 10% GL or more, preferably 20% GL or more, more preferably 50 GL% or more in measurement at 23 ° C. and 50% humidity. It is usually 400% GL or less, preferably 300% GL or less.

When the polyimide film has mechanical properties in such a range, it becomes a more durable polyimide film, which is preferable.

The present invention will be described in more detail below by way of examples. The following examples are shown for explaining the present invention in detail, and the present invention is not limited to the following examples unless contrary to the gist thereof.

[Substituent Amount I, Substituent Amount II, Total Substituent Amount]
The amount of amic acid residue (amide group, carboxylic acid group, carboxylic acid ester group) was determined by ¹ H-NMR measurement with a heavy DMSO solution of polyimide, and the terminal group (amino group, carboxylic acid, carboxylic acid ester group, carboxylic acid anhydride) was determined. ) Was determined from the ratio of the tetracarboxylic acid compound and the diamine compound at the time of production, and the total was taken as the substituent amount I.
The amount of substituents (amide group, amino group, nitro group, hydroxyl group, ester group, alkoxy group, halogen group, alkyl halide group) introduced into the main chain is determined from the introduced structure and its molar ratio, and the amount of substituents. It was designated as II.
The total of the above-mentioned substituent amount I and substituent amount II was taken as the total polyimide.

[Film molding]
A solution prepared by dissolving polyimide in DMAc so as to be 20% by mass was applied to a soda glass substrate using a 500 μm applicator, and dried at 330 ° C. for 30 minutes. Then, it was peeled off from the glass substrate to obtain a polyimide film having a thickness of 50 μm.

[Glass transition temperature (Tg)]
Using a dynamic viscoelastic analyzer (SII6100 manufactured by Hitachi High-Tech Science Co., Ltd.), the sample size was measured in a temperature range of room temperature to 430 ° C. at a sample size width of 6 mm, length of 20 mm, frequency of 10 Hz, and heating rate of 5 ° C./min. The peak of α relaxation of the curve plotting the loss tangent (tan δ) with respect to temperature was determined as the glass transition temperature (Tg).

[Bending resistance]
Using a MIT tester, a polyimide film having a width of 15 mm and a length of 110 mm was bent at a bending radius of 0.38 mm and a speed of 175 times / minute, and evaluated as the number of reciprocating bendings until the test piece broke.

[Yellow Index (YI)]
A yellow index per 50 μm thickness of the film was determined using a color computer manufactured by Suga Seiki Co., Ltd.

[Solvent content with boiling point of 150 ° C or higher]
^{1 By 1} H-NMR measurement, the amount of residual solvent was determined from the ratio of the signal based on the solvent and the signal based on the resin skeleton.

[Amount of residual solvent in 20% varnish]
A solution prepared by dissolving polyimide in methylene chloride so as to have a concentration of 20% by mass was determined in the same manner as the solvent content having a boiling point of 150 ° C. or higher.

[Particle size]
Using a particle size distribution meter (Microtrac HRA9320-x100), 30 mL of desalinated water was added to 50 mg of the sample, 1 mL of 0.1% Triton solution was added thereto, and then the solution dispersed for 5 minutes with an ultrasonic device was circulated at a circulation speed. It was measured at 40.

[Example 1]
57.1 g of 3,3', 4,4'-biscyclohexanetetracarboxylic dianhydride, in a four-necked flask equipped with a nitrogen gas introduction tube, a cooler, a Dean-Stark aggregator filled with toluene, and a stirrer. 29.5 g of m-trizine, 7.3 g of 1,5-diaminonaphthalene, 282 g of N-methyl-2-pyrrolidone (NMP), and 56 g of toluene were added, and the mixture was heated under reflux for 30 hours. Next, 0.7 g of triethylamine and 2.6 g of acetic anhydride were added in this order, and the mixture was stirred at 60 ° C. for 4 hours for chemical imidization. 420 g of N, N-dimethylacetamide (DMAc) was added to 70 g of the obtained reaction solution to dilute it, and the mixture was added dropwise to 3 L of isopropyl alcohol (IPA) and stirred for 30 minutes. The solid was separated by filtration and vacuum dried at 120 ° C. for 6 hours to obtain Polyimide 1. The molar ratio (CA / Am) of the tetracarboxylic dianhydride and the diamine compound used in the production of polyimide 1 was 1.008.

The amount of amic acid residue, the amount of terminal groups, the amount of substituents introduced into the main chain, the solvent content having a boiling point of 150 ° C. or higher, and the amount of 20% varnish residual solvent of the obtained polyimide 1 were determined, and the results are summarized in Table 1. It was.
Further, a film was formed using the obtained polyimide 1, and the obtained polyimide film was subjected to bending resistance, Y. I. , The glass transition temperature was measured, and the results are summarized in Table 2.

[Example 2]
Polyimide 2 (CA / Am =) was carried out in the same manner as in Example 1 except that 1,5-diaminonaphthalene in Example 1 was changed to 2,5-dimethyl-p-phenylenediamine to 6.3 g and NMP was changed to 279 g. 1.008) was obtained.
The obtained polyimide 2 and its polyimide film were evaluated in the same manner as in Example 1, and the results are summarized in Tables 1 and 2.

[Example 3]
The 3,3', 4,4'-biscyclohexanetetracarboxylic dianhydride of Example 1 was changed to 60.6 g, m-trizine was changed to 31.8 g, NMP was changed to 256 g, and toluene was changed to 51 g, 1,5-. Diaminonaphthalene was changed to 17.4 g of 4,4'-(9-fluorenylidene) dianiline, and the same method as in Example 1 was performed except that chemical imidization was not performed. Polyimide 3 (CA / Am = 0.99). ) Was obtained.
The obtained polyimide 3 and its polyimide film were evaluated in the same manner as in Example 1, and the results are summarized in Tables 1 and 2.

[Comparative Example 1]
Change 3,3', 4,4'-biscyclohexanetetracarboxylic dianhydride of Example 1 to 16.7 g, NMP to 221 g, toluene to 51 g, and m-trizine to 4,4'-diamino-2. Change 1,5-diaminonaphthalene to 6.3 g of 4,4-diaminobenzanilide to 26.4 g of -methyl-2'-trifluoromethylbiphenyl, and 2,2-bis (3,4-dicarboxyphenyl). The same method as in Example 1 was carried out except that 24.2 g of -1,1,1,3,3,3-hexafluoropropane dianhydride was added and no chemical imidization was performed. Polyimide 4 (CA / Am = 0.99) was obtained.
The obtained polyimide 4 and its polyimide film were evaluated in the same manner as in Example 1, and the results are summarized in Tables 1 and 2.

[Comparative Example 2]
Example 1 3,3', 4,4'-biscyclohexanetetracarboxylic dianhydride (60.6 g), m-trizine (31.8 g), NMP (241 g), toluene (48 g), 1,5-diaminonaphthalene Was changed to 10.8 g of 3,3'-dihydroxy-4,4'-diaminobiphenyl, and the same method as in Example 1 was carried out except that chemical imidization was not performed. Polyimide 5 (CA / Am = 0. 99) was obtained.
The obtained polyimide 5 and its polyimide film were evaluated in the same manner as in Example 1, and the results are summarized in Tables 1 and 2.

[Comparative Example 3]
The method was the same as in Comparative Example 1 except that 4,4'-diamino-2-methyl-2'-trifluoromethylbiphenyl was changed to 32.2 g and 4,4-diaminobenzanilide was not added, and the polyimide was used. 6 (CA / Am = 0.99) was obtained.
The obtained polyimide 6 and its polyimide film were evaluated in the same manner as in Example 1, and the results are summarized in Tables 1 and 2.

From the above results, by using polyimides 1 to 3 having a substituent amount I, a substituent amount II, a total substituent amount, and a solvent content having a boiling point of 150 ° C. or higher satisfying the requirements of the present invention, a polyimide having a low process load can be obtained. , Y. I. It can be seen that a polyimide film having a low value, excellent light transmission, and excellent bending resistance can be obtained.
On the other hand, the polyimides of Comparative Examples 1 to 3 have a large amount of substituents II and a large amount of total substituents, a large content of a solvent having a boiling point of 150 ° C. or higher, and a large amount of residual solvent of 20% varnish. It turns out that is high. In addition, the light transmittance and bending resistance of the obtained polyimide film were also inferior to those of the examples.

Claims (4)

The amount of substituents I defined below is 20 mol% or less, the amount of substituents II defined below is 10 mol% or less, and the total amount of substituents is the sum of the amount of substituents I and the amount of substituents II. Is 20 mol% or less, and the content of the solvent having a boiling point of 150 ° C. or higher is less than 5% by mass.
Substituent Amount I: Amic acid residue which is at least one of an amide group, a carboxylic acid group, and a carboxylic acid ester group contained in polyimide, and an amino group, a carboxylic acid group, a carboxylic acid ester group, and anhydrous. Total amount of substituents of terminal groups which are any one or more of carboxylic acid groups Amount of substituents II: Amid group, amino group, nitro group, hydroxyl group, ester group, alkoxy group introduced into the main chain of polyimide, Amount of functional group that is at least one of a halogen group and an alkyl halide group The polyimide according to claim 1, wherein the substituent amount I is 10 mol% or less, the substituent amount II is 8 mol% or less, and the total substituent amount is 15 mol% or less. A methylene chloride composition containing the polyimide according to claim 1 or 2, wherein the content of the solvent having a boiling point of 150 ° C. or higher is 5000 ppm or less. A polyimide film containing the polyimide according to claim 1 or 2.